Automatic control for venetian blind

ABSTRACT

Apparatus for automatically controlling a venetian blind is provided within a cornice box from which the blind is suspended. The apparatus includes a first and second drive motor for driving shafts provided with reels. Thus, in order to raise the blind a pair of cords, one on each side of the blind, is taken up by reels on a drive shaft being rotated by a first motor; and in order to lower the blind the pair of cords are played out from the reels by reversing the rotation of the first motor. The slats for the blind are supported by transverse cord members connected across a front and back cord provided on each side of the blind. Thus, in order to close the blind the front cord on each side of the blind is taken up by reels on a drive shaft being rotated by the second motor and the back cord on each side of the blind is simultaneously played out of reels on a drive shaft being rotated by the second motor; and in order to open the blind the direction of movements of the front and back cords is reversed by reversing the rotation of the second motor. Push buttons on a conveniently positioned panel provide for controlling the operation of the blind by selectively actuating the first and second motors.

[22] Filed:

United States Patent 1191 Ipekgil AUTOMATIC CONTROL FOR 'VENETIAN BLIND [76] Inventor: Ayhan Ipekgil, 301 8. Kenmore Ave., Los Angeles, Calif. 90020 June 29, 1972 [211 App]. No.: 267,566

52 us. c1. ..160/168 [51] Int. 01. E06b 9/30 [58] Field of Search ..160/166-178 [5 61 References Cited UNITED STATES PATENTS 2,017,541 10/1935 Kuyper 160/168 2,723,716 11/1955 Berni 160/168 3,310,099

4/1967 Hunter et al.; 160/171 Primary Examiner-Peter M. Caun [57] ABSTRACT Apparatus for automatically controlling a venetian [451 May 7, 1974 blind is provided within a cornice box from Which the blind is suspended. The apparatus includes a first and, second drive motor for driving shafts provided with reels. Thus, in order to raise the blind a pair of cords, one on each side of the blind, is taken up by reels on a drive shaft beingrotated by a first motor; and in order to lower the blind the pair of cords are played out from the reels by reversing the rotation of the first motor. The slats for the blind are supported by transverse cord members connected ac'ross a front and back cord provided on each side of the blind. Thus, in order to close the blind the front oord on each side of the blind is taken up by reels on a drive shaft being rotated by the second motor and the back cord on each side of the blind is simultaneously played out of reels on a drive shaft being rotated. by the second motor; and in order to open the blind the direction of movements of the front and back cords is reversed by reversing the rotation of the second motor. Push-buttons on a conveniently positioned panel providefor controlling the operation of the blind by selectively actuating the first and second motors.

5 Claims, 8 Drawing Figures PATENTEUHAY 7 IBM SHEET 1 OF 2 r 1 AUTOMATIC CONTROL FOR VENETIAN BLIND This invention relates to controls for window blinds conventionally provided with cords hanging from the side of the window which can be manipulated for raising and lowering the blind and for tilting its slats to any desired angle so as to regulate the light, heat or air admitted therethrough.

The principal object of thepresent invention is to provide a control means which operates in response to the depressing and holding down of push buttons. on a control panel to automatically control the raising or blind by varying the angle at which the slats are held.

In accordance with the present invention a cornice bow is provided for mounting on the top ofa window. A blind comprised of a plurality of horizontally disposed slats is suspended from the bottom of the-comice box by cords located on either side of the blind. Mounted within the cornice box is a first motor which drives a first shaft provided with a first pair of reels. Also mounted within the cornice box is a slower speed second motor which simultaneously drives both a second shaft provided with a second pair of reels and a third shaft provided with a third pair of reels. A first pair of cords having upper ends wound about the respective first pair of reels extends down through openings on the respective sides of the slats with their lower ends attached to a bottom member of the blind. A second pair of cords having their upper ends wound in one sense about the respective second pair of reels extend down along the front of the respective sides of the slats and about pulleys provided on the sides of the bottom member and then pass upwardly to form a third pair of cords which extend up alongthe back of the respective sides of the slats with their upper ends wound in the opposite sense about the respective third pair of reels. 'A panel located on the side of thewindow is provided with an fup, push button, a down push button, an open push button and a close push button. When the up push button is depressed, a circuit is closed which energizes the first motor in one direction to gather up the first pair of cords on the respective first pair of reels to raise the blind and when the down push button is depressed a circuit is closed which energizes the first motor in the opposite direction to play out the first pair of cords wound on the respective first pair of reels to lower the blind. When the close push button is depressed the circuit is closed which energizes the second motor in one direction to play out the second pair of cords wound on the respective secoud'pair of reels and to gather in the third pair of cords wound on the respective third pair of reels so as to cause the slats'to be tilted to. a substantially vertical position and thereby close the blind. When the open push button is depressed a circuit is closed which energizes the second motor in the opposite direction to gather in the second pair of cords wound on the respective second lowering of the blind and the opening or closing of the 2 pair of reels and to play out the third pair of cords wound on the respective third pair of reels so as to cause the slats to be returned to their level or open position. Q

With these and other objects in view, the invention consists of the various parts of thedevice whereby the objects contemplated are obtained, as herein set forth,

pointed out in theappended claims and illustrated in the accompanying drawings.

IN THE DRAWINGS.

FIG. 1 is a perspective view of a blind comprised of a plurality of horizontally disposed slats beingsuspended from a cornice box which encloses the automatic controls of the present invention;

.FIG. 2 is a side view of the lower portion of the blind taken along line 2-2 of FIG. l'and showing the slats disposed in a level or open position;

FIG. 3 is a detail view of a pulley enclosed in one end portion of the bottom frame member of the blind;

FIG. 4 is a view showing a transverse cord connected by its ends to the front and back tilt cords;

FIG. 5 is a side view of thelower portion of the blind slowing the slats disposed in a tilted orclosed position;

FIG. 6 is aside view of the upper portion of the blind showing the slats drawn together as a result of the blind FIG. 8 is an electrical diagram showin the circuit for operating the motors in response to push buttons to control the operation of the blind. g

Referring to FIG. 1, a cornice box 10 is shown mounted above the top of a window having a frame .11. A blind l2 comprised of a plurality of horizontally diss posed slats 13 and a horizontally disposed bottom member or rail 14 is suspended from below the cornice box 10 by three cords 16a, 17a, and 18a on the left side thereof and three cords 16b, 17b, and 18b on the right side thereof. The cords are made of a strong material such as nylon which can withstand considerable wear.

' The center cord 16a on the left side of blind 11 extends down from the base of the cornice box 10 through enlarged'openings 20a on the left end portions of each of the slats 13 and the lower end thereof is looped and fastened by a metal clip 21 to an eye hook 22aprovided on the left side of the upper surface of the bottom member 14. The front cord. 17a on the left side of the blind 11 extends down from the base of the cornice box 10 along the front of the slats l3 and the lower end thereof passes down through an opening 23a in the top of the bottom member 14 around a pulley 25a supported within the bottom member 14 on the left side thereof and then passesup through opening'24a to form the back cord which extends up along the back of the slats 13 into the base of the cornice box 10.

The center cord 16b on the right side of the blind 11 extends down from the base of'the cornice box 10 through enlarged openings 20b on the right end portion on each of the slats 13 and the lower endthereof is looped about and fastened by a metal clip 21 to an eye hook 22b provided on the right side of the upper surface of the bottom member 14. Thefront cord 17b on the right side of the blind 12 extends down from the base of the cornice box along the front of the slats l3 and the lower end passes down through an opening 23b in the top of the bottom member 14 around a pule ley b (FIG. 3) supported within the bottom'member 14 on the right side thereof and then passes up through an opening 24b on the top of member 14 to form the back cord 18b extending up along the back of the slats 13 into the base of the cornice box 10.

Connected across front cord 17a and back cord 18a on the left side of the blink 12 at each of a plurality of equally vertically spaced points along the length thereof is a transverse cord member 27a. As shown in F IG. 4, the ends of each of the cord members 27a are looped about points on the respective cords 17a and 18a and secured in position by use of metal clips 21. In a similar manner, connected-across front c'ord 17b and back cord l8b on the right side of the blind 12 at each of a plurality of equally vertically spaced points along the length thereof is a transverse cord member 27b. The respective ends of each of the cord members are looped about the respective cords 17b and 18b and se- 7 cured in position by the use of metal clips 21. It should now be clearly understood that the end portions of each of the slats 13 are supported on correspondingly leveled transverse cord members 27a and 27b.

Reference will next be made to FIG. 7 which shows a perspective view of the cornice box 10 with its top 35 and front wall 36 partially cut away to show apparatus included therein for automatically controlling the operation of the blind 12 in response to the depressing and holding down of push buttons provided on a panel 30 located at some convenient location such as the wall on the side of the window frame 11. The cornice box 10 includes a set of three pulleys 31a, 32a and 33a mounted therein on the left side of its base 34 and a set of three pulleys 31b, 32b and 33b mounted therein on the right side of the base 34.

Secured on the base 34 on the central portion of the cornice box 10 is a chassis 37. A first motor 41 is attached to the chassis 37 by a bracket 38 provided with screws 39 and a second motor 46 is attached to the chassis 37 by a bracket 50 provided with screws 51. A first shaft 42 extending from the right side of the first motor 41 has its outer end supported in a bearing pedestal 43 having a base attached by screws 45 to the chassis 37. Secured onthe first shaft 42 is a first pair of reels 44a and 44b. A second shaft 47 extending from the left side of the second motor 46 has its outer end supported in the bearing pedestal 43. Secured on the second shaft 47 is a second pair .of reels 48a and 48b. A thirdshaft 49 extending from the right side of the second motor 46 has its outer end supported in a bearing pedestal '54 having a base attached by screws 54a to the chassis 37. Secured on the third shaft 49 is a third pair of reels 52a and 52b. In order to reduce the weight of the apparatus enclosed in the cornice box 10 the motors 41 and 46 are small in size and the parts such as the chassis 37, the shafts 42, 47 and 49 and the bearing pedestals 45 and 54 are made of aluminum and the reels are made of a plastic material such as teflon and may be secured to the aluminum shafts by an epoxy cement.

Extending upwardly through three openings 53a on the left side of the base 34 of the cornice box 10 are the respective cords 16a, 17a and 18a. The center cord 16a passes around the pulley 32a on base 34 from which it 4 extends inwardly below thechassis 37 to a pulley 55a on base 34 and then upwardly so that its end can be wound about the reel 44a on the frist shaft 42. The

' front cord 17d passes around the pulley 31a on base 34 Likewise, extendingupwardly through three open- V ings 53b on the right side of the base 34 of the cornice box 10 are the respective ends of the cords 16b, 17b and 18b on the right side of the blind 12. The center cord 16b passes around pulley 32b on base 34 and extendsinwardly below the chassis 37 to a pulley55b on base 34 from which it is directed upwardly so that its end can be wound about the reel 44b on the first shaft 42. The front cord 17b passes around pulley 31b on base 34 and extends inwardly below the chassis 37 to a pulley 57b on base 34 from which it is directed upwardly so that its end canbe wound about the reel 48b on the second shaft 47. The back cord 18b passes around pulley 33b on base 34 and extends inwardly below the chassis 37 to a pulley 59b on base 34 from which it is directed upwardly so that its end can be wound about the reel 52b on the third shaft 49. 7

It should be noted that the first motor 41 andthe second motor 46 are of the type that can operate to rotate in either a clockwise or counterclockwise direction. Furthermore, the second motor 46 operates at a much lower revolution per minute, i.e., 0n the orderof l/24 the revolution per minute of the first motor 41.

It should now be clearly understood that the cords 16a and 16b on the respective sides of the blind 12 have their upper ends wound about the respective reels 44a and 44b securedon the first shaft 42 so that these cords are taken up when the shaft 42 is rotated in a clockwise direction as viewed in FIG. 7. Furthermore, the cords 17a and 17b on the respective sides of the front of the blind 12 have their upper ends connected about the respective reels 48a and 48b secured on the second shaft 47 so that these cords are then taken up when the shaft 47 is rotated in a clockwise direction; and the cords 18a and 18b on the respective sides of the back of the blind 12 have their upper ends connected about the respective reels 52a and 52b secured on the third shaft 49 so that these cords are played out when the shaft 49 is rotated in a clockwise direction.

An electrical cable 65 connected through the back of the cornice box 10'has leads connected to each of the motors 41 and 46. The first motor 41 has a first input lead 61 which, when energized, provides for rotatingits shaft 42 clockwise and a second input lead 62 which when energized provides for rotating its shaft 42 counterclockwise. Likewise, second motor 46 has a first input lead 63 which, when energized, provides for rotating its shafts 47 and 49 clockwise and a second input lead 64 which, when energized, provides for'rotating its shafts 47 and 49 counterclockwise.

An electrical circuit for controlling the motors 41 and 46 to thereby control the operation of the blind l2 is shown in FIG. 8. The circuit includes four switches. These switches are designated as an ?up switch 66, a

these four switches are provided on panel 30 located on the side of the window frame 11. Each of the push buttons is provided with a spring (not shown) which re quires that the push button be held down in order to closethe associated switch contacts.

Thus the up push putton 71, when depressed, closes the up switch 66 and provides for raising the blind 12. The down push button 72, when depressed, closes the down switch 67 and provides for lowering the blind 12. The close push button 73, when depressed, closes the close switch 68 and provides for tilting each of the slats 13 to any desired angle so as to I partly or completely close the blind; and the open push button 74, when depressed, closes the open switch 69 and provides for leveling each of the slats 13 to a horizontal position, that is, a position parallel to the floor so as to provide formaximum opening of the blind 12 to light, air or heat.

As shown in FIG. 8, an AC power source (not shown) is coupled by a transformer 56 across the lines 58 and 60 which are illustrated as extending vertically on the left and right sides of the diagram. A fuse 56a is provided in the line 58. Connected across the vertical lines 6 held in an inclined position by their supporting transverse members 27a and 27b, the close'push button 73 is depressed. Asa result of depressing and holding 58 and 60 are the parallel current paths of the control circuit. The current paths 75 and 76 are connected to line 58 by the up switch 67, respectively. The switches 66 and 67 are of the type that are mechanically interconnected in that .when the up push button 71, for example, is depressed a'switch contact 70 in the current path 76 is open to assure that the current path 76 is open even though the push button 72 may be simultaneously depressed. The switches 68 and 69 are similarly mechanically interconnected. Thus, as shown, when the up switch 66 is closed the current path75 leading to input lead 6] is closed which results in energizing the first motor 41 to rotate in a clockwise direction. It should now be clear that as long as the up button 71 is depressed the motor 41 rotates shaft 42 in a closewise direction and the pair of reels 44a and 44b take up the cords 16a and 16b and the blind 12 continues to be raised. When the raising of the bottom member 14 causes the uppermost slat 13 of the blind 12 to reach a level near the base of the cornice box 14, an

arm 77 of an over travel limit switch 78 (FIG. 6) is acv tuated to disconnect the power across the current path 75 and stop the first motor 41 from being operated even through the up push button 71 is still depressed.

pair of reels 44a and 44b play out the cords 16a and 16b and the blind l2 continues to be lowered.

Next to be described is the electrical circuit provided for opening and closing the blind 12, that is, leveling or tilting the slats 13 to vary the amount of light, air or heat passing therethrough. FIG. 1 shows the blind 12in 6 its lowered position with the horizontal slats in their level or open position. If it is desired to close the blind 12, that is, to tilt the respective slats 13so that they are down the close push button 73, the close switch 68 located in current path 79 connected to input lead 63 of motor 46 is closed and the second motor 46 is energized to slowly rotate in a clockwise direction. As a result, the pair of cords 17a and 17b are taken up on the reels 48a and 48b and the pair of cords 18a and 18b are played out from the reels 52a and 52b which result in the front of the slats 13 being slowlytilted upwardly and the back being tilted at the same rate downwardly, as shown in FIG. 5, so as to close the blind 12. When the slats 13 have been tilted to provide the desired closing of the blind l2, releasing the close push button 73 stops the clockwise rotation of the second motor 46 and the blind l2 stays in the desired closed position.

push button 74 down the second motor 46 continues to be energized to slowly rotate in the counter clockwise direction causing the shaft 47 and therefore the reels 48a and 48b secured thereon to rotate and slowly play out the pair of cords 17a and 17b connected to the front of the slats l3 and causing the shaft 49 and therefore the reels 52a and 52b secured thereon to rotate and slowly take up the pair of cords 18a and 18b connected to the back of the slats 13. When he slats 13 have reached a level position at which the blind 12 is opened the desired amount, releasing the open" push button 74 stops the motor 46 and the slats stay at that position. V

It should be noted that by having the integrally joined lower portion of cords 17a and 18a looped around the pulley 25a mounted on one end of the bottom member 14 and by having the integrally joined lower portion of cords 17b and 18b looped around the pulley 25b mounted on the other end of the bottom member 14- playing out of the; back cords 18a and 18b, or vice versa.

It should be further noted that the vertical spacing of the transverse cord members 27a and 27b on the re-.

spective sides of the blind 12 may be closer together so I that a lesser amount of the intervening vertical length of the cord 17a, 18a and 17b, 1812 will be gathered up when the blind 12 is raised, as illustrated in FIG. 6.

While the preferred embodiments of the invention have been shown and described it should be understood that the present invention should not be limited thereto but that the invention is intended to embrace all embodiments coming within the scope of the claims which follow.

l. A Venetian blind provided with an automatic control, the combination comprising:

a casing, a first reversible motor mounted in said casing, said first motor having a drive shaft, a pair of first reels on the drive shaft of said first motor, a pair of first pulley means, a pair of first cords, each of said cords being wound on a reel of said pair of first reels and guided by said pair of first pulley means to respectively extend down from the opposite end portions of said casing,

a second reversible motor mounted in said casing, said second reversible motor having a drive shaft,

a pair of second reels and a pair of third reels on the drive shaft of said second motor,

a pair of second'pulley means and a pair of third pulley means,

a pair of second cords, each of said cords being wound on a reel of said pair of second reels and guided by said pair of second pulley means to respectively extend down from the opposite end portions and said casing,

a pair of third cords, each of said cords being wound on a reel of said pair of third reels in a sense opposite to the direction in which the pair of second cords is wound on the pair of second reels and guided by said pair of third pulley means to respectively extend down from the opposite end portions of said casing,

plurality of vertically spaced transverse cord members connected across one of the cords of the pair of second cords and one of the cords of the pair of third cords extending down on either of the end portions of the casing,

a plurality of horizontally disposed vertically spaced slats, each slat having its outer end supported below either of the end portions of said casing by a transverse cord member,

a bottom rail,

each of the cords of the pair of first cords, respectively extending down through aligned openings in either of the end portions of said slats and having its lower end connected to said bottom rail, and

an electrical circuit for separately energizing and controlling the direction of rotation of said first and second motors,

whereby when said first motor is energized, said pair of first cords is wound on or played out from said .pair of first reels to cause said bottom rail and said plurality of slats to be raised or lowered, and

whereby when said second motor is energized, said pair of second cords is wound or played out from said pair of second reels while said pair of third cords is simultaneously played out or wound on said pair of third reels to cause said slats to be either tilted to a closed position or disposed in a substantially horizontal open position. v

2,. The apparatus in accordance with claim 1;

wherein said electrical circuit includes a control panel provided with an up push button, a down push button, a close push button, and an open push button,

whereby while said up push button is being depressed, said first motor is rotated in one direction to wind said first pair of cords about said first pair of reels to raise the blind and while said down push button is being depressed said first motor is rotated in the opposite direction to unwind said first pair of cords from said first pair of reels to lower the blind, and

whereby while said close push button is being depressed said second motor is rotated in one direction to wind said second pair of cords about said 10 ing;

second pair of reels and to play out said third pair of cords from said third pair of reels to close the blind, and while said open push button is being depressed said second motor is rotated on the opposite direction to play out said second pair of cords from said second pair of reels and to wind said third pair of cords about said third pair of reels to open the blind.

3. The invention in accordance with claim 1 includa pulley mounted on either end of said bottom rail,

and

wherein thelower end of one of the cords of the second pair of cords and the lower end of the other of the cords of the third pair of cords extending down from each end of the casing are integrally joined and passed around a respective one of thepulleys on either end of the bottom rail 4. The invention in accordance with claim 1 wherein the revolutions per minute of the second motor is on the order of l/24th the revolutions per minute of the first motor. I

5. A Venetian blind provided with an automatic control, the combination comprising:

a casing,

a plurality of pairs of tilt cords extending down from said casing, each of said pairs of tilt cords including a back and front tilt cord,

a plurality of vertically spaced transverse members connecting the front and back tilt cords of each pair,

a plurality of horizontally disposed, vertically spaced slats supported between said back and front tilt cords by said transverse members,

at least two lift cords, each extending down from said casing through aligned openings provided in the slats between pairs of back and-front tilt cords,

a bottom rail attached to the lower ends of said lift cord,

a first reversible motor mounted in said casing, said first motor having a drive shaft,

a first pair of reels on the drive shaft of said first motor,

a first pair of pulley means insaid casing for guiding the lift cords to enable the upper ends thereof to be respectively wound about said first pair of reels,

a second reversible motor mounted in said casing,

said second motor having a drive shaft,

A first and second set of reels on said drive shaft 0 said second motor,

a first set of pulley means in said casing for guiding the front tilt cords to enable the upper ends thereof to be respectively wound about the reels of said first set of reels,

a second set of pulley means in said casing for guiding the back tilt cords to enable the upper ends thereof to be respectively wound about the reels of said second set of reels in a sense opposite to the direction in which the front tilt cords is wound on the reels of said first set of reels, and

control means for individually controlling the energization and the direction of rotation of said first and second motors. 

1. A Venetian blind provided with an automatic control, the combination comprising: a casing, a first reversible motor mounted in said casing, said first motor having a drive shaft, a pair of first reels on the drive shaft of said first motor, a pair of first pulley means, a pair of first cords, each of said cords being wound on a reel of said pair of first reels and guided by said pair of first pulley means to respectively extend down from the opposite end portions of said casing, a second reversible motor mounted in said casing, said second reversible motor having a drive shaft, a pair of second reels and a pair of third reels on the drive shaft of said second motor, a pair of second pulley means and a pair of third pulley means, a pair of second cords, each of said cords being wound on a reel of said pair of second reels and guided by said pair of second pulley means to respectively extend down from the opposite end portions and said casing, a pair of third cords, each of said cords being wound on a reel of said pair of third reels in a sense opposite to the direction in which the pair of second cords is wound on the pair of second reels and guided by said pair of third pulley means to respectively extend down from the opposite end portions of said casing, a plurality of vertically spaced transverse cord members connected across one of the cords of the pair of second cords and one of the cords of the pair of third cords extending down on either of the end portions of the casing, a plurality of horizontally disposed vertically spaced slats, each slat having its outer end supported below either of the end portions of said casing by a transverse cord member, a bottom rail, each of the cords of the pair of first cords, respectively extending down through aligned openings in either of the end portions of said slats and having its lower end connected to said bottom rail, and an electrical circuit for separately energizing and controlling the direction of rotation of said first and second motors, whereby when said first motor is energized, said pair of first cords is wound on or played out from said pair of first reels to cause said bottom rail and said plurality of slats to be raised or lowered, and whereby when said second motor is energized, said pair of second cords is wound or played out from said pair of second reels while said pair of third cords is simultaneously played out or wound on said pair of third reels to cause said slats to be either tilted to a closed position or disposed in a substantially horizontal open position.
 2. The apparatus in accordance with claim 1; wherein said electrical circuit includes a control panel provided with an ''''up'''' push button, a ''''down'''' push button, a ''''close'''' push button, and an ''''open'''' push button, whereby while said ''''up'''' push button is being depressed, said first motor is rotated in one direction to wind said first pair of cords about said first pair of reels to raise the blind and while said ''''down'''' push button is being depressed said first motor is rotated in the opposite direction to unwind said first pair of cords from said first pair of reels to lower the blind, and whereby while said ''''close'''' push button is being depressed said second motor is rotated in one direction to wind said second pair of cords about said second pair of reels and to play out said third pair of cords from said third pair of reels to close the blind, and while said ''''open'''' push button is being depressed said second motor is rotated on the opposite direction to play out said second pair of cords from said second pair of reels and to wind said third pair of cords about said third pair of reels to open the blind.
 3. The invention in accordance with claim 1 including; a pulley mounted on either end of said bottom rail, and wherein the lower end of one of the cords of the second pair of cords and the lower end of the other of the cords of the third pair of cords extending down from each end of the casing are integrally joined and passed around a respective one of the pulleys on either end of the bottom rail.
 4. The invention in accordance with claim 1 wherein the revolutions per minute of the second motor is on the order of 1/24th the revolutions per minute of the first motor.
 5. A Venetian blind provided with an automatic control, the combination comprising: a casing, a plurality of pairs of tilt cords extending down from said casing, each of said pairs of tilt cords including a back and front tilt cord, a plurality of vertically spaced transverse members connecting the front and back tilt cords of each pair, a plurality of horizontally disposed, vertically spaced slats supported between said back and front tilt cords by said transverse members, at least two lift cords, each extending down from said casing through aligned openings provided in the slats between pairs of back and front tilt cords, a bottom rail aTtached to the lower ends of said lift cord, a first reversible motor mounted in said casing, said first motor having a drive shaft, a first pair of reels on the drive shaft of said first motor, a first pair of pulley means in said casing for guiding the lift cords to enable the upper ends thereof to be respectively wound about said first pair of reels, a second reversible motor mounted in said casing, said second motor having a drive shaft, A first and second set of reels on said drive shaft of said second motor, a first set of pulley means in said casing for guiding the front tilt cords to enable the upper ends thereof to be respectively wound about the reels of said first set of reels, a second set of pulley means in said casing for guiding the back tilt cords to enable the upper ends thereof to be respectively wound about the reels of said second set of reels in a sense opposite to the direction in which the front tilt cords is wound on the reels of said first set of reels, and control means for individually controlling the energization and the direction of rotation of said first and second motors. 